Laser module is an important product which is applied to the various industrial fields such as semiconductor, display, automobile, defense, medical instrument, and the like. Laser module is named differently depending on the material being used, and the most widely used product is the semiconductor diode pumping laser module based on a solid state crystal. Oscillation of a specific wavelength according to the absorption and the energy transition becomes possible by illuminating the crystal such as Nd:YAG crystal with a high power semiconductor pumping diode or a flash lamp as an excitation source. In this way, by configuring a resonator having a solid state crystal wherein a pumping light source is used as an excitation source, a laser having a desired wavelength can be oscillated, and a laser module having a desired energy can be manufactured. Besides, a pulse laser can be manufactured by configuring with a Q-switching module inside the resonator. If a wavelength conversion technology is applied using a nonlinear optical crystal, laser modules having various wavelengths from infrared to UV can be manufactured. And thus, laser modules having various wavelengths, energies, and pulses can be manufactured, and applied to various application fields.
Meanwhile, a solid state laser module has a monochromatic property, and is often manufactured as a module generating a particular wavelength by combining a second harmonic generator and a third harmonic generator. (Refer to U.S. Pat. Nos. 6,115,402, 5,835,513, 5,742,626, and 5,144,630.)
A solid state laser module generates a fundamental laser light by the input from the pumping light source. Generally, a 1064 nm fundamental laser light is generated by using 808 nm wavelength diode pumping, and a YAG crystal doped with 1.0% Nd, and at this time, the efficiency between 20 to 30% can be obtained. A second harmonic wave and a third harmonic wave can be generated by inputting the fundamental laser light into a wavelength variable crystal like LBO. For example, LBO crystal having cutting angles of φ=0° and θ=90° can be used for generating 532 nm from 1064 nm. In this case, temperature is required to be set around 150° C., and this is referred to as ‘non-critical phase matching.’ A third harmonic wave of a UV wavelength can be generated by inputting 1064 nm and 532 nm wavelength lights into a wavelength variable crystal like LBO. For example, LBO crystal having cutting angles of θ=42° and φ=90° can be used. In this case, temperature is required to be set about 40 to 50° C.
The optical elements having the above described features are arranged into an intracavity structure or an extracavity structure, and they are aligned and fixed therein so as to generate a desired wavelength, and such technique can be referred to as the manufacturing technology of a solid state laser module.
Q-switching is a technology used for manufacturing a pulsed light having a narrow line width among the solid state laser module manufacturing technologies. Generally, the Q-switching technologies are classified into: A-O Q-switching and E-O Q-switching; or an active Q-switching using a mechanical type Q-switching and the like, and a passive Q-switching adopting a saturable absorption method wherein a crystal such as Cr:YAG crystal is used. Q-switching elements are provided inside the resonator for generating a fundamental laser light having a pulse width less than a nanosecond.
According to the laser module manufacturing method of the prior art, components are disposed on the designed optical path, and after manually aligning the components one by one, the optical components are fixed thereto by using fastening means like screws, and thus, there are problems in that the efficiency and the stability of the laser module are being degraded.